Four top CPS officials in Abilene, suspects in the probe, already are on forced leave while the criminal investigation proceeds. No charges have been filed.

“I've been aware that Commissioner Baldwin is interested in new opportunities,” Texas Health and Human Services Executive Commissioner Kyle Janek said Thursday. “Howard has a distinguished career in public service, and I commend him for his many years serving the state's most vulnerable citizens.”

Last month, the Houston Chronicle confirmed that police officers were investigating CPS workers' handling of the death of 22-month-old Tamryn Klapheke. She was found dead of dehydration in her Dyess Air Force Base home on Aug. 28, six days after CPS closed its third neglect investigation involving the family.

The toddler and her two sisters, then ages 6 months and 3, were reportedly left by their mother, Tiffany, without food or water for as long as a week. All three girls suffered chemical burns from lying in urine-soaked bedding. Their mother remains in the Taylor County Jail.

Documents obtained by the Chronicle showed CPS caseworker Claudia Gonzalez closed the most recent investigation of the children's safety without a supervisor's signature and without visiting the Klapheke children. Both actions violate CPS policy, and Gonzalez has resigned.

An Abilene search warrant affidavit details suspicions that CPS regional administrator Bit Whitaker, who worked under Baldwin; former program director Gretchen Denny; and CPS supervisor Barbara McDaniel, who was later reprimanded by CPS, tampered with evidence involving the Klapheke death investigation.

All three women, and a fourth, Geneva Shroeder, program administrator over investigations, were placed on leave.

Tamryn's case was one of hundreds of delinquent and backlogged CPS cases across the state that languished without resolution. Another child, Julia Martinez of Houston, died in August as her case sat on a CPS worker's desk for months.

Abilene Police Chief Stan Standridge said his office is waiting for state District Judge Lee Hamilton to assign a special prosecutor or prosecutors in Tamryn's case because lawyers in the county district attorney's office may be witnesses in the criminal investigation. “We are now ready to engage the special prosecutor about where this case proceeds,” he said.

The Department of Family and Protective Services employs 10,621 workers across the state; 8,363 work for CPS.

Baldwin's resignation was a surprise to state Sen. Carlos Uresti, D-San Antonio, who is a member of the Senate Committee on Health and Human Services. “I was surprised and I'll say somewhat disappointed because I've known Howard for many, many years,” Uresti said. “I don't know the reasons behind it, but I'll be sad to see him go.”

Baldwin, a San Antonio attorney who has worked for three state agencies, was named commissioner in January. He told his staff Thursday that his resignation is effective at the end of the month, according to the Health and Human Services Commission spokeswoman, Stephanie Goodman.